Locking device for throtile valves



Aug. 31, 1943. e. H. FUEHRER LOCKING DEVICE FOR THROTTLE VALVES Filed Aug. 5, 1941 W r RM Y m w m m vH W m A m? 4m H Patented Aug. 31, 1943 LOCKING DEVICE ron rnnorrpn-vapvns George H. Fuehrer, Phillipsburg, N. J., assignor to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application August 5, 1941, Serial No. 405,483

1 Claim.

This invention relates to throttle valves, and more particularly to a locking device for throttle valves of the rotary type used for controlling the admission of pressure fluid into rock drills and similar machines.

In many machines of this type, the working implement extends loosely into the rock drill to receive the blows of a hammer piston and it is, therefore, essential that means be provided to prevent the unintentional starting of the rock drill because of the danger of ejecting the drill steel from its guide and causing injuries to the operator.

It is accordingly an object of the invention to preclude the possibility of accidentally setting the rock drill in operation.

Another object is to enable the throttle Valve controlling the admission of pressure fluid into the rock drill to be positively locked against unauthorized rotative movement and to provide a convenient and positive means for releasing the throttle valve.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is a side elevation of the rearward portion of a rock drill, the throttle valve of which is equipped with a locking device constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 2-2 showing the locking device in its locking position, and

Figure 3 is a view similar to Figure 2 illustrating the manner in which the locking device may be disengaged from the throttle valve.

Referring more particularly to the drawing, 20 designates the rearward end of a rock drill cylinder wherein may be arranged a hammer piston (not shown) and a valve mechanism (not shown) for distributing pressure fluid to the ends of the cylinder.

On the rearward end of the cylinder 20 is a back head 2| secured to the cylinder 20 by bolts 22 and having a valve chamber 23 for the accommodation of a throttle valve 24. The valve chamber 23 is tapered, as is also the valve 24, and the large end of the valve chamber is sealed by a plug 25 having a bore 26 to accommodate a conduit 21 that may lead from a suitable source of pressure fluid supply.

Within the throttle valve is a recess 23 that opens from the large end of the throttle valve, and a port 29 in the wall of the throttle valve aifords communication between the recess 28 and a supply passage 30, in the back head 2|, leading to the distribuitng valve mechanism.

On the small end of the throttle valve 24 is a stem 3| that extends from the side of the back head 2| into the hub 32 of a lever 33 whereby the throttle valve may be manually rotated. A key 34 in the hub 32 and the stem 3| prevents relative rotation between the throttle valve and the lever, and a nut 35 threaded on the free end of the stem 3| bears against the hub 32 to retain it on the stem 3|.

In accordance with the practice of the invention, means are provided to lock the throttle valve against unauthorized rotary movement and to enable the throttle valve to be conveniently and quickly released whenever it is intended to rotate it from its closed position to a position for admitting pressure fluid into the rock drill. To this end the back head 2| is provided with an aperture 38 to receive a reciprocatory pin 31 that is cylindrical throughout its length and is freely rotatable in the aperture, and in the bottom of the aperture 36 is a spring Is to act against the pin 31 for urging it outwardly, in the direction of the hub 32.

The hub 32 also has an aperture designated 38 which, in what may be termed the closed position of the throttle valve, lies coaxial with the aperture 3B. The portion of the aperture 38 directly confronting the aperture 36 constitutes a socket 39 of larger diameter than the aperture 36 to receive the end of the pin 31 which is suitably proportioned to enable it to readily enter the socket.

Within the aperture 38 is a plunger 40 having a head 4| that has a slide fit in the socket 39 and seats at its free end against the end of the pin 31. The opposite end of the plunger 40 extends exteriorly of the hub 32 and carries a button 42 that extends slidably into an enlarged portion 43 of the aperture. A spring 44 in the enlarged portion 43 acts against the inner surface of the button 42 to hold the head 4| normally against the bottom of the socket 39.

In practice, whenever it is intended to release the throttle valve so that it may be rotated from its closed to an open position the plunger 40 is depressed from the position illustrated in Figure 2 to that shown in Figure 3 to move the free end of the head 4| flush with or slightly beyond the open end of the socket 39. The throttle valve may then be conveniently rotated to an open position, and after the plunger 40 has been moved out of the plane of the pin 31 the button 42 may be released and the end of the pin 31 will thereafter bear aganist the inner end surface of the hub 32.

Whenever, as after a drilling operation, the throttle valve is again rotated to its closed position to cut off the supply of pressure fluid to the rock drill, the socket 39 is moved into alignment with the pin 31 which will then enter the socket and again lock the throttle valve against unintentional rotary movement.

I claim:

A locking device, comprising a casing having a chamber, a rotary member therein, a lever for the rotary member having an aperture, a springpressed cylindrical pin slidable and rotatable in the casing having a cylindrical portion to extend into the aperture for holding the rotary member against rotary movement, a spring-pressed plunger slidable in the aperture and having a head of larger diameter than the pin for moving the pin out of the aperture to release the rotary member, and cooperating means on the lever and the plunger for retaining the plunger in the lever.

GEORGE E. FUEHRER. 

